World History Archive / Alamy Stock Photo

Today, Jan. 27, marks the 72nd anniversary of the liberation of Auschwitz. That event did not mark the end of the Holocaust—gassings continued until the eve of Hitler’s suicide on April 30, 1945, and thousands more died of the effects of starvation and mistreatment at places like Belsen even weeks after their liberation.

But Jan. 27 should put us in mind of the beginnings. How did this happen? In particular, how could Germany, by all outward indications a civilized and modern country, become a persecuting society, brutally indifferent to the fates of anyone outside its supposed “people’s community”?